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Re: [PATCH 1/1] stp: rt: replace spin_lock with stp style lock and use STP_ALLOC_FLAGS
- From: David Smith <dsmith at redhat dot com>
- To: yzhu1 <yanjun dot zhu at windriver dot com>, sshukla at mvista dot com, systemtap at sourceware dot org
- Date: Tue, 17 Nov 2015 10:45:17 -0600
- Subject: Re: [PATCH 1/1] stp: rt: replace spin_lock with stp style lock and use STP_ALLOC_FLAGS
- Authentication-results: sourceware.org; auth=none
- References: <1447747786-29733-1-git-send-email-yanjun dot zhu at windriver dot com> <1447747786-29733-2-git-send-email-yanjun dot zhu at windriver dot com>
On 11/17/2015 02:09 AM, yzhu1 wrote:
> From: Zhu Yanjun <yanjun.zhu@windriver.com>
>
> -rt mode spin lock lead to __might_sleep calltrace.
> Replacing spin lock with stp type raw lock and
> changing STP_ALLOC_SLEEP_FLAGS to STP_ALLOC_FLAGS solves the problem.
I have the same comment I had before. The raw lock changes are fine, but
I still don't believe the STP_ALLOC_SLEEP_FLAGS change is correct, at
least not without some further explanation. In the call trace below,
STP_ALLOC_SLEEP_FLAGS wasn't used from what I can tell.
Did you get a chance to try running systemtap with your raw lock changes
and the added might_sleep() call patch I sent you?
> Call Trace:
> [<ffffffff818d83f1>] dump_stack+0x19/0x1b
> [<ffffffff81070e3f>] __might_sleep+0xef/0x160
> [<ffffffff818de710>] rt_spin_lock+0x20/0x50
> [<ffffffff81178699>] d_path+0x79/0x1a0
> [<ffffffffa0047be9>] __stp_get_mm_path.constprop.79+0x49/0x90 [stap_f5bb3e3c9b162aab5a51afc2375fe9cf_2073]
> [<ffffffffa004d01b>] __stp_utrace_attach_match_tsk.isra.53+0x7b/0x1b0 [stap_f5bb3e3c9b162aab5a51afc2375fe9cf_2073]
> [<ffffffffa004d18c>] __stp_utrace_task_finder_report_exec+0x3c/0x50 [stap_f5bb3e3c9b162aab5a51afc2375fe9cf_2073]
> [<ffffffffa0047b59>] utrace_report_exec+0xb9/0x100 [stap_f5bb3e3c9b162aab5a51afc2375fe9cf_2073]
> [<ffffffff811674b2>] search_binary_handler+0x332/0x380
> [<ffffffff81168d0c>] do_execve_common.isra.24+0x55c/0x640
> [<ffffffff81168e08>] do_execve+0x18/0x20
> [<ffffffff81169082>] SyS_execve+0x32/0x50
> [<ffffffff818e6979>] stub_execve+0x69/0xa0
--
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
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